1. Field of the Invention
The present invention relates to a process for dry printing of information. The process involves forming a magnetic image on a master followed by decorating the magnetic image with ferromagnetic toner particles which are then electrostatically transferred to a dielectric substrate and fixed in place.
2. Description of the Prior Art
Both Xerography and magnetography are known. Xerography involves: forming an electrostatic charge on a photoconductive material such as selenium; imagewise exposing the photoconductive material to light whereby the exposed areas lose their charge; and applying a pigmented, finely divided, electrically charged powder which is attracted to and held on the electrostatic image. The charged toner image is then transferred to copy paper either with an opposite electrostatic charge or by means of pressure.
In magnetography a magnetic image is formed, and ferromagnetic particles applied thereto which adhere to the magnetized areas of the image. The particles are then transferred to copy paper either by pressure or magnetically. The pressure technique causes objectionable wear to the imaging member and can also cause buildup of a film on the imaging member which causes smudging.
In magnetic transfer it has been found difficult to effect transfer of toner without erasing the latent magnetic image on the imaging member.